Physics Quiz-13
Assertion - Reasoning Type
If an object changes its position with respect to its surroundings with time, then it is called in motion. It is a change in the position of an object over time. Motion in a straight line is nothing but linear motion. As the name suggests, it’s in a particular straight line, thus it can be said that it uses only one dimension.
Q1. 
Solution
According to definition, displacement= velocity × time
Since displacement is a vector quantity so its value is equal to the vector sum of the area under velocity-time graph
Q2.
Solution
Equation of motion can be applied if the acceleration is in opposite direction to that of velocity and uniform motion mean the acceleration is zero.
Q3. 
Solution
In kinematical equations, mass does not appear.
Q4. 
Solution
When the body reverses the direction of motion it is momentarily at rest, but it still possesses acceleration. Velocity zero does not mean that acceleration is also zero.
Q5.
Solution
Negative slope of position time graph represents that the body is moving towards the negative direction and if the slope of the graph decrease with time then it represents the decrease in speed i.e. retardation in motion.
Q6. 
Solution
Position- time graph for a stationary object is a straight line parallel to time axis showing that no change in position with time.
Q7.
Solution
A body has no relative motion with respect to itself. Hence if a frame of reference of the body is fixed, then the body will be always at relative rest in this frame of reference
Q8.
Solution
Since velocity is a vector quantity, hence as its direction changes keeping magnitude constant, velocity is said to be changed. But for constant speed in equal time interval distance travelled should be equal
Q9. 
Q10. 
Solution
Since velocity is a vector quantity, hence as its direction changes keeping magnitude constant, velocity is said to be changed. But for constant speed in equal time interval distance travelled should be equal.
